Engine Trouble strange ping in ht motor...

Discussion in '2-Stroke Engines' started by battery, Mar 28, 2014.

  1. battery

    battery Member

    so recently I have been hearing a pinging on occation it sounds like the flicking of an empty soup can. I have pulled apart my motor at 1200 miles now and every thing seems to be in working order. no play on any bearings. but the piston rings do seem to have more play in them than usual. and I have been runninjg it at wot almost all the time. has anyone heard this noise before? I figure it might be the rings snagging but cannot be sure.
     

  2. velzie

    velzie Member

    It would benefit to know what mods you have done: you have a jag cdi and SBP shift kit, right? any compression mods?What fuel to oil ratio do you use? Did you do a plug chop to check for a lean condition before the motor made the noise?
     
  3. battery

    battery Member

    I have recently cleaned up the ports and widened them all ever so slightly. I have just installed my jag cdi a week ago. I do have the sbp shift kit installed. frequently running through left side chain as it is stretching very fast! I have always had the carb needle to its richest setting and have not had any problems running lean. I am switching to jn's Wabron chineese racing carb for hopefully more fuel air flow tonight or tomorrow. the plug is a chalky brown color, the cylender head and piston is black and both look normal. I run a 20:1 semi synth oil as to the manufacturer specs.
     
  4. jaguar

    jaguar Well-Known Member

    Does it happen during mid range RPM under heavy load? If so then it could be detonation.
    Change switch 1 on the CDI for less input resistance. Look at the blue in this drawing:
    CDI-3sw3.gif
    If it happens at high RPM then most likely it is pre-ignition which can be from too hot a spark plug or too much crud on it. Read my recent post about detonation. Check the crank seals to make sure they aren't leaking and allowing a lean condition (which may not be detected by reading the spark plug).
     
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  5. battery

    battery Member

    It seems to be at mid range rpm under lighter load. I lost compression yesterday after pulling off the head. I don't think I seated the head gasket right. I'm going to buy a new engine so I have a backup. This one has been run to hell.
     
  6. jaguar

    jaguar Well-Known Member

    Is there any aluminum "powder" sticking to the piston or head?
    Ideally aluminum gaskets are to be changed for new ones each diasassembly because they conform to the irregularities of the head and cylinder just one time. I actually prefer to make my own gasket out of gasket material. It seals much better.
     
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